Improvement in pistons for steam-engines



regalati tat'm "www @fina w anni www H. N. J. MANSFIELD, OF MALONE, N EW YORK.- Lmm Patent No. 83,188, camz octava 2o, 186s.

The Schedule referred to in these Letters Patent and making part ofthe same..

To all Iwho/m, 'it fnul/y camara:

Beit known that I, H. N. J. MANSFIELD, of Malone, in the county of Franklin, and in the State of New York, have invented certain new and useful Improvements in Pistons for Steam-Engines; and do hereby declare that the following is a full, clear, and exact description thereof', reference being had to the accompanying drawings, and to the letters of reference marked thereon.

In the presenti ordinary style of cylinder, horizontal, the whole weight of the piston-head and rod is continually borne by the lower inside of the cylinder, and bythe stuiIing-box, causing a rapid wear of the lower cylinder, on its bottom and sides, also a wear of the sniffing-box, as well as of the packing-rings and followers of the piston-head. From this it results that the best piston-head soon becomes leaky, and the stuifing-box and cylinder are cut downwards.

The design of my invention is to prevent this wear by constructing the piston-head in the manner here inafter described, so that there shall be an upward pressure of the steam exactly suiicient to counterbalance the weight of the piston-head and rod.

In order to enable others skilled in the art to make and use my inventionI will now proceed to describe its construction and operation, referring to the annexed drawings, which form a part of this specification, and which represent a vertical section of a steam-cylinder, showing my `counter-balance on steam-piston.

G is the lower inside of cylinder, on which the piston-head rests and moves, and on which comes the wearlof the piston, and which it is the purpose of my improvement to prevent;

B B are the followers of the piston-head;

G C packing-rings ofthe piston-head;

F, stuffing-box;

D D', steam-ports; and v respectively the upper and lower lips of the which constitute my improvement,

A A', follower,

In the drawings, the 'arrows show the way in which the steam is brought to bear upon the piston.

The steam entering through the steam-port D passes to A, which is a lip or projecting flange from the follower. This lip should have a surface suiiiciently large for the upper pressure of the steam to counterbalance the weight of piston-head and rod.

For example, if the piston-head and rod weigh two hundred pounds, having a pressure of fifty pounds to the square inch, then it is found that a lip having a surface 'of four inches, will allow an upward pressure of two hundred pounds, just sucient to balance the gravity of the piston, and permitting it to move backwards and forwards comparatively free from friction, and without wearing the cylinder or box.

In new-made cylinders, the e'omplish the purpose.

In old cylinders, which have been worn down, and where steam lmight easily pass above the lip A, the purpose is accomplished by y'making a lip, A', at the bottom of the follower, by takingout or sinkjng a segment of its surface, as shown in the drawingg'or both lips may be used on and the upward pressure divided between the two lips.

This Yimprovement is applicable for all horizontal cylinders, for air, steam, or water.

Having thus fully described my invention,

The construction of the piston-head for horizontal cylinders, with the projecting lip A and indentation A', near its periphery, whereby to obtain upward pressure of steam, all substantially as herein set forth.

lip A is suicient to ac- In testimony that I claim the foregoing, I have here- 25th day of August, 1868.

unto set my hand, this H. N. J. MANSFIELD.

Witnesses:

ROYAL Comun, J. H. MOORE.

and the engine is run with steam.

the follower at the same time,

and desire to secure by Letters n 

